Image forming apparatus and warm-up method

Abstract

An electrophotographic image forming apparatus and method of controlling the apparatus during a warm-up operation. During the warm-up operation, a heating unit for heating a fuser will be turned on and a motor for starting rotation of a photosensitive body will be activated when the temperature of the fuser reaches a motor rotation start temperature. When the temperature of the fuser reaches a warm-up completion temperature, the warm-up operation will be stopped and the rotation of the photosensitive body will be terminated. The warm-up completion temperature is higher than a stand-by temperature but lower than a fusing temperature.

What is claimed is:  
     
       1. A warm-up method for an image forming apparatus, comprising: 
       (a) starting a warm-up operation;  
       (b) activating a heating unit that heats a fuser, and starting the rotation of a motor that rotates a photosensitive body when the temperature of the fuser reaches a motor rotation starting temperature,  
       (c) detecting the temperature of the fuser;  
       (d) determining whether or not the detected temperature of the fuser is equal to a warm-up completion temperature, the warm-up completion temperature being higher than the stand-by temperature; and  
       (e) stopping the motor rotation and ending the warm-up operation when it is determined in step (d) that the temperature of the fuser has reached the warm-up completion temperature.  
     
     
       2. The warm-up method of  claim 1  further including the step of (f) maintaining the temperature of the fuser at the stand-by temperature after step (e). 
     
     
       3. The warm-up method of  claim 1  wherein the warm-up completion temperature is lower than a fusing temperature. 
     
     
       4. The warm-up method of  claim 1  wherein the stand-by temperature is 100° C. and the warm-up completion temperature is about 150° C. 
     
     
       5. An electro-photographic image forming apparatus, comprising: 
       (a) means for starting a warm-up operation;  
       (b) means for activating a heating unit that heats a fuser, and starting the rotation of a motor that rotates a photosensitive body when the temperature of the fuser reaches a motor rotation starting temperature,  
       (c) means for detecting the temperature of the fuser;  
       (d) means for determining whether or not the detected temperature of the fuser is equal to a warm-up completion temperature, the warm-up completion temperature being higher than the stand-by temperature;  
       (e) means for stopping the motor rotation and ending the warm-up, operation when it is determined in step (d) that the temperature of the fuser has reached the warm-up completion temperature; and  
       (f) means for transporting a recording sheet from a paper cassette to the photosensitive body when the fuser reaches a print starting temperature.  
     
     
       6. The apparatus of  claim 5 , further including the means for maintaining the temperature of the fuser at the stand-by temperature. 
     
     
       7. The apparatus of  claim 5 , wherein the warm-up completion temperature is lower than a fusing temperature. 
     
     
       8. The apparatus of  claim 5 , wherein the stand-by temperature is about 100° C. and the warm-up completion temperature is about 150° C. 
     
     
       9. The warm-up method of  claim 1 , further comprising: 
       (f) transporting a recording sheet from a paper cassette to the photosensitive body when the fuser reaches a print starting temperature.  
     
     
       10. A warm-up method for an image forming apparatus, comprising: 
       (a) starting a warm-up operation;  
       (b) activating a heating unit that heats a fuser, and starting the rotation of a motor that rotates a photosensitive body;  
       (c) detecting the temperature of the fuser;  
       (d) determining whether or not the detected temperature of the fuser is equal to a warm-up completion temperature, the warm-up completion temperature being higher than the stand-by temperature;  
       (e) stopping the motor rotation and ending the warm-up operation when it is determined in step (d) that the temperature of the fuser has reached the warm-up completion temperature; and  
       (f) transporting a recording sheet from a paper cassette to the photosensitive body when the fuser reaches a print starting temperature.  
     
     
       11. The warm-up method of  claim 10 , wherein (b) activating a heating unit that heats a fuser, and starting the rotation of a motor that rotates a photosensitive body, comprises: 
       (b) activating a heating unit that heats a fuser, and starting the rotation of a motor that rotates a photosensitive body when the temperature of the fuser reaches a motor rotation starting temperature.